The present application relates to a traction apparatus that is used for traction performed in osteopathy, orthopedics, or the like and a traction force control method for the traction apparatus.
As for a conventional traction apparatus of this type, there has been proposed a sitting traction apparatus that is provided with a sling device for slinging up the underarms of a patient and a seat position that has a fixture for fixing the thighs, and so by hoisting the seat portion (upper half of the patient's body) vertically, treats the lumbar and the like (for example, refer to Japanese Unexamined Patent Application, First Publication No. 2003-88540).
Also as a conventional traction apparatus, there has been proposed a traction apparatus that has a load cell that detects traction force, and along with detecting traction force, is constituted so as to use the detection signal for drive control of a motor that is a drive source of traction force (for example, refer to Japanese Unexamined Patent Application, First Publication No. S59-118156).
A conventional traction apparatus displays the traction force on a display portion based on the detection output of a load cell serving as a traction force sensor during traction force control. This display uses an analog/digital conversion value (A/D value) of the output of the load cell, and a digital/analog conversion value (D/A value) that is a control signal corresponding to the traction force that has been set. This A/D signal and D/A signal use corrected values.
However, there are cases of the zero point of the output of the load cell that is a traction force sensor fluctuating due to a transitional state immediately after electrical power activation, an environmental change, or changes over time. Fluctuation of the zero point of a traction sensor directly influences the detection value of the traction force. Due to this influence, there has been the problem of not being able to accurately carry out traction force control.
As such, there is a need to provide a traction apparatus that is capable of accurately performing traction force control and a traction force control method for the traction apparatus.